The purpose to this project has been extended to include both the continuation of our work on the enzymes involved in the initial step in the degradation of the neuroactive compound, lambda-hydroxybutyrate, as well as the initiation of experiments which will be used to investigate the interaction of lambda-hydroxybutyrate with several 2nd messenger systems. Work on the mitochondrial transhydrogenase with catalyzes the alpha- ketoglutarate-dependent oxidation of the lambda hydroxybutyrate has included further purification of the enzyme as well as kinetic and inhibitor studies. Initial studies on the effect of lambda-hydroxybutyrate on C-AMP production in neural tissues have been carried out. These studies will be extended to include the effect of lambda-hydroxybutyrate on C-GMP production and on calcium transport.